Manchester native Harrison Williams, now a junior at Worcester Polytechnic Institute, was at his ham radio command post in Brookline on April 15 of last year, coordinating the "Bus Net" system for the Boston Marathon, when two explosions rocked the finish line on Boylston Street.

"Everything was operating smoothly. We were doing the job we needed to do, and then they stopped everyone in the room," he said. "Our job stayed the same, but the goal changed."

Williams and his partner had been dispatching buses to gather up runners along the route — runners who were unable to finish the race and needed transportation into Boston.

After the explosions, they switched gears.

"We were able to communicate with the buses on their way into Boston, turn them around, and started to do the sweep in a reverse fashion, up the course and away from Boston," he said. "We were using the units we had available to pick up as many people as we could, get them off the course and bring them to safe locations."

This year, Williams has been asked to once again co-lead the "Bus Net" system at the Boston Marathon on Monday, where he'll be joined by 15 other members of WPI's Wireless Association.

Ham radio enthusiast

Despite all the advances in communication technology, the old ham radio networks operating on FCC-approved frequencies still have unique value, said the ham radio enthusiast — and that value was demonstrated on Marathon Monday 2013.

Cell phone networks crashed under the sheer volume of calls as thousands of runners and their families tried to connect amid the chaos. Walkie-talkies with their short range were of limited value.

"They have a range of about 500 feet, and we're talking about a 26-mile course," he said.

The ham radio network operated seamlessly, as Williams communicated from his base station to radio-operators with hand-held devices on each of the 30-plus buses used as part of the "Bus Net" service.

At one point, Williams had to provide directions to a bus driver over the ham radio network.

"All the buses have GPS locators, so we can see what street they are on at any given point in time," he said. "One driver had no idea how to get to where he needed to go, so I used Google maps to direct the bus, turn by turn, to where they needed to get to."

On a normal Boston Marathon day, the Bus Net transports around 1,000 or more runners who simply cannot complete the course, Williams said.

Last year that number tripled, as more than 3,000 runners had to be transported by the Bus Net to two staging areas in Newton.

Steve Schwarm of Wrentham, Mass., a WPI alumni and electronics and software engineer, is the man who for 14 years has overseen the volunteer amateur radio operators manning the communication system used along the 26-mile course, from the start to the finish.

Last year, there were 250 hams, as they are called, but another 50 will be on hand this year with the beefed up security. Williams, he said, will be one of four amateur radio operators whose job it will be to coordinate communication between the First Aid tents, where injured or ill runners are taken, and getting them to the designated bus stop.

Schwarm said it's like setting up a separate city bus system for the marathon. He anticipates that this year about 2,000 runners won't finish the race — twice as many as usual — and they will need transportation off the course.

He said there are 36,000 runners this year, up from 27,000 last year; about 4,000 of them did not have to qualify for the marathon because they are running for charities. It is the charity runners who usually don't finish the raise and who will need help, Schwarm said.

"It's a challenging job," he said of Williams' role.

A family tradition

Born in Londonderry and raised in Manchester, Williams is completing his junior year at WPI, where he majors in electrical computer engineering.

"I'm a fourth-generation electrical engineer," he said. "I guess I was exposed to it from an early age. It's always been something I've wanted to do."

He also took up the ham radio hobby at an early age. "I was first licensed as an amateur radio operator in my senior year of high school," said the 2011 Trinity grad. "My grandfather and father are also amateur radio operators, so it runs in the family."

Once at WPI, he joined the WPI Wireless Association and his fascination with the technology that dates back to the early 20th century intensified. The WPI base station was first licensed in 1909 and went on the air in 1916.

"They do a lot of public safety work, all of it as volunteers," he said. "That got me started in the public service aspect of amateur radio. Every year, the club has sent at least 20 or more volunteers to the Boston Marathon to be part of the communication group at various locations. It was something I got involved with in my freshman year and I just stuck with it."

Williams says his involvement with the Wireless Association has improved his skills as a radio operator, while at the same time enhancing his appreciation of the many volunteers in the ham radio community, and the service they provide.

Amid the tragedy of last year's explosions, that volunteer spirit was particularly in evidence.

"There is this entire community that goes there to help and volunteer," he said, "not just the ham radio operators. Everyone did a good job of staying cool, calm and collected throughout the whole incident, and did what was needed to get people to safety."

North Korea has been moving airplanes and boosting defenses on its east coast after the United States dispatched B-1B bombers to the Korean peninsula over the weekend, South Korea's Yonhap News...

Vintage World War II planes are on display this week at Keene's Dillant-Hopkins Airport in North Swanzey.

Treasury Secretary Steve Mnuchin defended President Donald Trump's way of dealing with North Korea, insisting Sunday that heated rhetorical exchanges with reclusive despot Kim Jong-un were not making...